Already registered to two computers?

[Trevor]

Sorry to keep nagging folks, but I've twice e-mailed support@mtu.com as instructed by the installation screen, and posted on the Registration problems forum, but still not had a reply?
My main karaoke computer is having a few sound problems, so if possible, I'd like to have the peace of mind of a backup system before the weekend gigs. I'm hoping to have the sound problems sorted by then, but just in case.....

Original message:

Hi all,
I have just tried to install Hoster on my home computer, but got the message that it is already registered on two different computers.
It's only been installed on my Karaoke computer, as I've been waiting until my home PC was upgraded before loading it onto there too. This upgrade happened only this week, so I'm not sure which other computer is registered?
The only thing I can think of, is that the actual download files were downloaded onto my old home computer, but installed on my karaoke PC.

The details of the computers as far as I know, are as follows.

Old home computer:
Athlon K1000A 256mb ram
Win XP Pro

Karaoke computer:
Athlon 2.4ghz, 512 mb ram (I think)
Win XP Pro

New home computer:
Athlon64 3.0 ghz
1gb ram
Win XP Pro

Any ideas?
Thanks in advance
Trevor